This invention relates to electrical coil forms and more particularly to electrical coil forms having molded-on plastic brackets into which connector sleeves are located for strain relieved connections with the ends of the electrical coil windings and also with the ends of external leads.
One type of coil form with a connector piece is known from U.S. Pat. No. 3,932,828. In the coil form specified in U.S. Pat. No. 3,932,828 a plastic terminal block is fixed-mounted to one end flange in such a way that one set of connector sleeve ends project beyond the internal working side of the plastic block and are located radially above the compartment the coil is to be wound in and therefore impede the insertion of the coil winding within the winding compartment, especially when using automatic winding machines. The connector sleeves themselves are inserted from the external working side of the plastic block in the fitting openings located on said side having a larger opening diameter strain relief. Projection against tension exerted by the external connecting lines is provided primarily by bending the straps after inserting the sleeves around the sleeve ends which project beyond the internal working side of the plastic bracket. Protection against the sleeves slipping through when inserted from the external working side of the plastic block is provided by a collar rim to be separately mounted on the sleeves, which mates at the inner end of the fitting opening mating part having a larger opening diameter on a step-formed indentation. To cover and insulate the free ends of the sleeves, which project beyond the winding compartment, an insulating encapsulant is applied axially.
In another coil form known from German Pat. No. 2,758,700, during the injection molding, tongue-shaped connector pins are molded simultaneously with a hinge-like plastic bracket to the coil form. In the operating position of the plastic bracket, after it has been swung on its hinged axis over the winding compartment against the one end flange and which catches in the other end flange, the winding ends of the exciter coil wound in the coil form are connected to the radially inward projecting internal terminals; a plug attached to an external connecting leads can be mounted onto the radially outwards projecting external terminals of the injection-molded connecting pins.
It is the object of this invention to simplify the fabrication of the coil form and to ensure reliable strain-relieved contact between the winding ends of the coil wound on the coil form on the one hand and the connecting ends of the external connecting leads on the other hand, particularly for purposes of automated fabrication and assembly of a completed coil.